It can happen to anyone, and it can happen anywhere — on an airplane or a city street, in a second grade classroom or at a midnight movie screening, on a college campus or in the middle of a shopping center parking lot.

For the post-9/11 generation of young Americans, violence is not an abstraction. It’s on their turf and in their face, whether it’s the work of foreign or domestic terrorists or of individuals fueled by inexplicable rage or untreated mental illness.

It’s not the fear of widespread doom, like the nuclear threat of the 1950s. It’s two bombs exploding at the finish line of a celebrated race, as they did last week in Boston. Three young people were killed — Martin Richard, 8, Lingzi Lu, 23, and Krystle Campbell, 29. Dozens more were maimed or severely injured.

While events like that are sporadic and infrequent compared with the dreary regularity of inner-city violence, this brand of 21st-century carnage is magnified by blanket media coverage. For the current generation, known for its plugged-in devotion to the latest technology, the Internet cranks up rumors and speculation and, with them, anxiety. So what are they going to do about it?

For today’s 18- to 21-year-olds, the Boston bombings must feel like a bookend to what started on Sept. 11, 2001. They were elementary school kids when terrorists brought down the twin towers of the World Trade Center.

They remember where they were, just like members of a previous generation of elementary school kids remember where they were on Nov. 22, 1963.

Because of 9/11, this new generation grew up in an America where security checks are the norm. Belts and shoes are routinely shed during airport security checks, backpacks are searched at museums, and water bottles are confiscated at baseball parks.

Of course, every generation has its traumas and tragedies, and sometimes they inspire greatness. World War II had that effect on those who fought the enemy overseas. When the war was over, the soldiers returned home to start families and build a better, stronger country.

In the 1960s, young people were devastated by the assassinations of inspirational leaders like John F. Kennedy, Robert F. Kennedy, and Martin Luther King Jr. But back then, the bad guys were after the big guys. The threat felt less personal to average citizens. It was a challenge to the political agendas of specifically targeted individuals, and it inspired a generation to take up the causes of their lost leaders. In the memories of the dead, the children of the ’60s committed themselves to public service. They marched for civil rights and equal rights and against war. A country divided on those issues eventually reached enough consensus to bring about dramatic changes of law and culture.

The violence on 9/11 inspired great acts of individual courage and heroism on the part of police, firefighters, and other first responders. So far, it has done the opposite of launching any great cause. The fear it brought makes people less tolerant and smaller in their vision and thinking.

To fight the so-called war on terror, the country gave up a degree of privacy and freedom in exchange for safety and security, some of it illusory. What happened at the Boston Marathon will doubtless inspire more restrictions. There will be a brief moment of rallying, during which New York Yankees fans will sing “Sweet Caroline.” But the old, depressing politics of terror will ultimately break out again and continue to divide the country along ideological lines — unless today’s generation does something to stop it.

The violence that broke out in Newtown, Aurora, and Tucson also inspired individual acts of courage and heroism. The teachers who put their bodies between the shooter and the tiny students of Sandy Hook exemplify that spirit of sacrifice. But so far, the pleas by parents of the children killed in that rampage by a young man with a semiautomatic rifle have not been enough to inspire a major overhaul of gun legislation.

Perhaps it’s time for the generation that inherited this world of fear and violence to do something about changing it.